A multi-disk clutch 6 is provided with a reduced thickness so that the size of devices, such as a transmission employing the multi-disk clutch 6 can also be reduced. The multi-disk clutch 6 is configured to transmit and interrupt a torque between a radially outer wall 52 and a second cylindrical portion 69 of a spline hub. The multi-disk clutch 6 includes a plurality of first friction plates 50 and a plurality of second friction plates 51. Radially outer portions of the first friction plates 50 are coupled in a circumferential direction to the radially outer wall 52. Each second friction plate 51 has a core plate 90 and a friction facing 51a. The core plate 90 has a friction mounting portion opposed to the first friction plate 50, and tooth portions. The tooth portions are in mesh with the second cylindrical portion 69 of the spline hub. The friction facing 51a is joined to the friction mounting portion. The friction mounting portion has a smaller thickness than the tooth portion.